Starfish with well developed and usually conspicuous marginal plates, forming a distinct, mostly vertical margin along the edge of the disc and arms. The marginal plates are as a rule more or less covered by spines or granules, sometimes however they are covered only by soft skin, in which case the plates are less distinct. The papulae are usually confined to the aboral side. The aboral side may be covered with paxillae or scattered spines, or it may be wholly naked.
Tube-feet and pedicellariae
The pedicellariae, if present, are of the simple spiniform or pectinate or valvate type, never of the crossed type and are never attached to the skin by means of a soft stalk. The tube-feet are always in two series.
- Family Astropectinidae
- Family Goniasteridae
- Family Poraniidae
- Family Luidiidae
The families Astropectinidae and Luidiidae are often placed in the order Paxillosida Perrier, 1884, whereas the Goniasteridae and Poraniidae are classified within the order Valvatida Perrier, 1884.